logbook: kanban for ai agents

logbook is a kanban board implementation for autonomous agentic development, focusing on autonomous development and context window management.

→ new here? see quickstart.md to get running in 2 minutes.

problem

ai agents changed the way software teams worked, and with specification-driven development we encounter a rift: agents don't manage their tasks as we do.

what's the issue with this?

• hard for humans to track autonomous work properly: "do you know what specific tasks your agent did?"
• hard for agents to track tasks in-progress and done: not a centralized way to track tasks so each instance haves to figure this out
• existing tools add too much overload and are human-centered: if an agent is going to use it, then it should be tailored for agents

solution

logbook is a file-system based kanban board that uses jsonl files to enter one task per line in a structured and clean approach and gives the agent the right tools to use it:

tools

• the agent can call list_tasks(status) and receive a list of the tasks in that status (in_progress by default)

• the agent can call current_task() and receive the highest-priority in_progress task for the current session, resolved via this priority chain:

  | priority | condition | action | |----------|-----------|--------| | 1 | task already assigned to this session | return highest priority (tie-break: oldest) | | 2 | unassigned in_progress task | claim highest priority, return | | 3 | in_progress task with a dead-session assignee | claim highest priority, return | | 4 | todo task | auto-transition highest priority to in_progress, claim, return | | 5 | nothing available | fail with no_current_task |

• the agent can call update_task(id, new_status, comment) to transition a task, add a comment, or reply to a need_info blocking comment

• the agent can call create_task(input) to open a new task in backlog, passing predictedKTokens so the server derives a Fibonacci estimation automatically

• the agent can call edit_task(id, updates) to change mutable fields without altering status

each one of these tools has the sole purpose of removing overload from the agent context, handling the "heavy load" programmatically on the MCP server or CLI.

cli

in addition to the MCP server, logbook provides a CLI for direct command-line usage:

# create a task
logbook create-task --project myproject --milestone v1 --title "Fix bug" \
  --definition-of-done "Bug fixed and tested" --description "Details..." \
  --predicted-k-tokens 3

# list tasks
logbook list-tasks --status in_progress
logbook list-tasks --status "*"

# get current task
logbook current-task

# update task status
logbook update-task --id <uuid> --new-status in_progress

# edit task
logbook edit-task --id <uuid> --title "New title"

# initialize project
logbook init
logbook init --force  # ensures both AGENTS.md and CLAUDE.md exist

all commands output JSON to stdout for easy parsing:

{"ok": true, "task": {...}}
{"ok": false, "error": {"code": -32001, "message": "Task not found", ...}}

see logbook --help for full documentation.

walkthrough

a complete agent session from start to done:

1. agent starts — get current task

current_task()
→ { id: "abc-123", title: "implement login endpoint", status: "in_progress", ... }

2. agent needs clarification — blocks on a question

update_task("abc-123", "need_info", {
  title: "which auth provider?",
  content: "should i use jwt or session-based auth? the spec doesn't say.",
  kind: "need_info"
})
→ hook fires: user is notified with the comment

3. user replies — task unblocked

update_task("abc-123", "in_progress", {
  id: "<comment-id>",
  reply: "use jwt, see the auth spec in docs/auth.md",
  title: "jwt confirmed",
  content: "jwt confirmed",
  kind: "need_info"
})
→ task returns to in_progress

4. agent finishes — submits for review

update_task("abc-123", "pending_review", {
  title: "implementation complete",
  content: "jwt login endpoint implemented, tests passing",
  kind: "regular"
})
→ review-spawn hook fires: review task created, reviewer agent spawned

5. reviewer approves — task closed

# reviewer agent calls:
current_task()  → gets the review task
update_task("<review-task-id>", "done")
→ original task abc-123 → done automatically

how the agent knows logbook exists

add the logbook MCP server to your AI client config (see configuration), then include these instructions in your agent's system prompt or CLAUDE.md:

You are connected to the logbook MCP server. Call current_task() immediately at session start.

the full system prompt is injected automatically when the MCP server connects.

architecture

• runtime: Bun / TypeScript
• effect system: Effect.ts — all async operations and errors are modeled as Effect<A, E, R>
• architecture: hexagonal (ports & adapters), organized by vertical slices per domain concept (task, hook)
• validation: Zod at every system boundary (MCP input, filesystem reads)
• persistence: JSONL — one task per line, append-only writes, full file scan for reads

JSONL was chosen for simplicity and agent-friendliness: a single line = a single task makes partial reads and diffs readable without tooling.

hooks

besides the tools that the agent call manually, each action performed in the kanban can have automatic hooks executed right before or after. the default hooks include:

• after moving a task to need_info, the user receives a notification with the comment left to be able to answer the question.
• after moving a task to pending_review, a reviewer sub-agent spawns and a review task is automatically generated for it.
• when a second task is moved to in_progress, a built-in hook fires and requires a comment justifying the overlap before proceeding.

but hooks can also be defined by the user as scripts in any language as long as it's installed in the system, under the "hooks/" directory, following this structure:

hooks/
└── example_hook/
    ├── config.yml
    └── script.ts

a minimal config.yml looks like:

# config.yml
event: task.status_changed   # lifecycle event that triggers the hook
condition: "new_status == 'need_info'"  # optional; JS-like expression
timeout_ms: 5000             # optional; default 5000

you can base your config.yml in the default hooks-which have complete configuration files.

note: as mentioned, you can change .ts for any language, but the .yml / .yaml is required for configuration.

review flow

when a task is moved to pending_review, the built-in review-spawn hook automatically creates a review task and spawns a reviewer sub-agent. the reviewer classifies every finding before acting:

flowchart TD
    PR[task: pending_review]
    PR -->|review-spawn hook| SPAWN[review task created\nreviewer agent spawned]
    SPAWN --> CL{classify findings}

    CL -->|nice-to-have findings| TD["[tech debt] tasks created\nin backlog — silently"]

    CL -->|must-fix found| MF[original → in_progress\nneed_info: must fix before re-submitting]
    CL -->|consider only| CO[original → in_progress\nneed_info: implementer decides\nfix now or backlog]
    CL -->|clean| DONE[original → done]

    MF --> RD[review task → done]
    CO --> RD
    DONE --> RD

    TD -.->|accompanies any outcome| RD

| finding severity | original task | review task | side effect | |-----------------|---------------|-------------|-------------| | must-fix | → in_progress + need_info | → done | — | | consider | → in_progress + need_info | → done | implementer replies: fix now or backlog | | nice-to-have | unchanged | — | [tech debt] backlog task created | | clean | → done | → done | — |

nice-to-have findings are always handled silently — they never block progress or ping the implementer.

why hooks?

hooks don't need to store information from one execution to the other, so the main principle here is: "execute and forget", this way we can focus on the kanban and actual tasks.

contracts

the core types the server operates on:

type Agent = {
  id: string,       // session_id assigned by the server on connection
  title: string,
  description: string
}

type Status = 'backlog' | 'todo' | 'need_info' | 'blocked' | 'in_progress' | 'pending_review' | 'done'

type Comment = {
  id: string,
  timestamp: Date,
  title: string,
  content: string,
  reply: string,  // user's reply, populated when responding to a need_info comment
  kind: 'need_info' | 'regular'  // drives the reply cycle — only need_info comments accept replies
}

type Task = {
  project: string,
  milestone: string,
  id: string,
  title: string,
  definition_of_done: string,
  description: string,
  estimation: number,      // fibonacci number derived from predictedKTokens at creation time
  comments: Comment[],
  assignee: Agent,
  status: Status,
  in_progress_since?: Date // set when task enters in_progress; used as tie-breaker in current_task
  priority: number         // integer ≥ 0; higher = more urgent; defaults to 0
}

// status defaults to 'in_progress'; results ordered by priority DESC
// project and milestone are optional; all provided filters compose (AND semantics)
type ListTasks = (options: { status: Status | '*', project?: string, milestone?: string }) => Task[]

// returns the highest-priority task for the current session using a priority chain:
// 1. own in_progress → 2. unassigned in_progress → 3. orphaned in_progress
// (dead-session assignee) → 4. highest-priority todo (auto-transitioned) → 5. no_current_task error.
// within each step, tasks are ordered by priority DESC, tie-broken by in_progress_since ASC.
// if a second task is moved to in_progress, a built-in hook fires and
// requires a comment justifying the overlap.
type GetCurrentTask = () => Task

// transitions a task to a new status; sessionId is injected server-side.
// to reply to a need_info comment, pass a comment with the existing comment's id and a reply string.
type UpdateTask = (id: string, new_status: Status, comment: CommentInput | null, sessionId: string) => void

type CommentInput = {
  id?: string,     // existing comment id — only when replying to a need_info comment
  title: string,
  content: string,
  reply?: string,  // reply text — only meaningful when id refers to a need_info comment
  kind: 'need_info' | 'regular'
}

// creates a new task in backlog assigned to the calling session.
// predictedKTokens is mapped to a Fibonacci estimation by the server.
type CreateTask = (input: CreateTaskInput, sessionId: string) => Task

type CreateTaskInput = {
  project: string,
  milestone: string,
  title: string,
  definition_of_done: string,
  description: string,
  predictedKTokens: number,  // positive number; server maps this to a Fibonacci estimation (max 20)
  priority?: number           // integer ≥ 0; defaults to 0
}

// edits mutable fields without changing status
type EditTask = (id: string, updates: EditTaskInput) => Task

type EditTaskInput = {
  title?: string,
  description?: string,
  definition_of_done?: string,
  predictedKTokens?: number,  // re-derives estimation if provided
  priority?: number            // integer ≥ 0; re-assigns priority if provided
}

each MCP session is treated as a distinct agent instance. the server assigns a session_id on connection and uses it to scope GetCurrentTask — no explicit agent ID needs to be passed by the caller.

install

npm install -g @bosun-sh/logbook

requires bun ≥ 1.0.0 as the runtime (install bun).

verify the installation:

logbook --version
# or
logbook-mcp --version

for a full onboarding walkthrough see quickstart.md.

configuration

quick setup

run logbook init in your project directory to scaffold:

• tasks.jsonl — the task store
• hooks/ — directory for custom hooks
• AGENTS.md and CLAUDE.md — documentation for AI agents

by default:

• if neither AGENTS.md nor CLAUDE.md exists → creates AGENTS.md and symlinks CLAUDE.md to it
• if only AGENTS.md exists → appends logbook docs to AGENTS.md
• if only CLAUDE.md exists → appends logbook docs to CLAUDE.md

use logbook init --force to ensure both files exist (appends to existing, creates/symlinks missing).

environment variables

| Variable | Default | Description | |----------|---------|-------------| | LOGBOOK_TASKS_FILE | ./tasks.jsonl | path to the JSONL task store | | LOGBOOK_HOOKS_DIR | ./hooks | directory scanned for custom hook definitions | | LOGBOOK_LOG_LEVEL | warn | structured logger level: debug, info, warn, or error |

gitignore

tasks.jsonl, sessions.json, and .logbook-session are runtime files generated by logbook — they should not be committed to version control:

tasks.jsonl
sessions.json
.logbook-session

note: the logbook repo itself intentionally commits these files for dogfooding — that is the exception, not the rule.

client setup

Claude Code — add to .claude/settings.json:

{
  "mcpServers": {
    "logbook": {
      "command": "logbook-mcp"
    }
  }
}

OpenCode — add to opencode.json:

{
  "mcp": {
    "logbook": {
      "type": "local",
      "command": ["logbook-mcp"],
      "enabled": true
    }
  }
}

security

hook conditions are trusted code

hook config.yml files support an optional condition field (e.g. "new_status == 'pending_review'"). these conditions are compiled and evaluated as live JavaScript at runtime — equivalent in trust level to a shell script.

what this means for you:

• only add hooks from sources you trust. a malicious config.yml condition can execute arbitrary code in the process that runs the MCP server.
• do not expose LOGBOOK_HOOKS_DIR to external write access. if an untrusted process can write files under the hooks directory, it can inject conditions that execute as the MCP server's user.
• the built-in hooks shipped with logbook are safe — they use simple equality checks (new_status == 'need_info').
• if a condition throws or is malformed, the hook is skipped silently and execution continues — it fails safe.

the security model here is the same as running a Makefile or a .husky/ script: filesystem-level trust. as long as you control what goes into your hooks directory, you are safe.

stability

logbook follows semantic versioning. here is what is stable at v1.0.0:

• mcp api: tool names and required parameters will not change within a major version. optional parameters may be added.
• jsonl format: the serialized Task type in tasks.jsonl is stable. new optional fields may be added; existing fields will not be removed or renamed within a major version.
• hook config schema: the event, condition, and timeout_ms keys in config.yml are stable. new optional keys may be added.
• breaking changes: any breaking change will be preceded by a deprecation notice in the prior minor release and documented in CHANGELOG.md.